Any place that can get your rig into their bay can do it. Pick a place you trust. Since it is a gas engine, it takes "normal" motor oil. Check your owner manual for the type and weight. Any quality brand should be fine.

I think it calls for 5w20 motorcraft semi-synthetic. Now we can argue till the cows come home over oils. You can probably put any brand name in and the engine will outlast the RV. They do rev high so I followed the more often schedule.

I use Castrol Edge full synthetic in the motor home. Change it myself. I have a drain pan that seals up and I just return the used oil to wherever I bought the new. I use the Edge Synthetic high mileage version in the Jeep because it's got over 150k on it. I've used Castrol oils for years in everything I've owned and never had a problem.

I am with old-crow, I use Castrol in my Ford gas engines, don't know why but I like using Motorcraft filters, I know they don't make filters, must be a psychological thing. Been using Castrol in all my gas engines and Rotella in my Diesels and Mobile-1 in my GL1800 Goldwing. Never had an engine problem that was oil or oil filter related.

You can use synthetic if you like - whatever weight/grade the owner manual states for engine oil. No different whether synthetic or standard oil.

Isn't it an E450 rather than F450? An RV on an F450 would be rare, but it is possible. If it's an E450 van under the RV, many Ford dealers and local oil change shops will handle it as a routine item. Just ask to make sure they have room for a tall vehicle (give them the height of your rig).

Never had a failure do to engine oil failure. By the way the weight of oil has little to do with its lubricating properties. It's the Viscosity Index that does. 5-20 or 10-30 are viscosity indexes and have nothing to do with how much the oil weighs.

While what you say about viscosity vs weight is technically true, since I was knee-high to a grasshopper it has been common for a lot of folks to talk about 30-weight oil, for example, so keep slang and common use in mind.

When we had a gasser we used 5W-30 Full Synthetic - we could go back and forth and too and fro on manufacturer but notionally they are all certified to the same SAE standard and therefor manufacturer should not matter. I always went with whatever was on sale the week I change it. We could also go around and around regrading standard, blend or full synthetic. My thought is that the Ford Triton V10 revs up to what I view as extreme RPMs when climbing a hill and therefor the full synthetic might protect and cool the motor and motor components more efficiently.